Plasmonic CH4 Sensor Using an MIM Waveguide with a Hexagonal Cavity and Silver Square Island

A metal-insulator-metal (MIM) waveguide with a regular hexagonal-shaped cavity has been used to simulate a plasmonic refractive index (RI) sensor. To improve the sensing performance, a silver square island is placed in this hole in a planned way. The dielectric material within the cavity is Ultraviolet curable fluoro-siloxane (UVCFS), which has been used to measure different concentrations of methane gas. The results show that 1902.6 nm/RIU (7.23 nm/%) is the maximum sensitivity. There are many ways that this sensor can be used in health, photonics, and optoelectronics.